The present invention relates to a transducer device for measuring mechanical values on hollow bodies, such as the internal pressure in pipes, by detecting deformations in the outer surface thereof, comprising a housing for removably enclosing the hollow body whose outer surface deformation is to be measured and at least one elastic sensor element being elastically and at least indirectly pressed against the outer surface of said hollow body by an elastic endorsing element and capable of stretching due to the deformation of said hollow body due to frictional contact therewith and is connected to the necessary leads for transmission of the measuring signals.